Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

545
FXUS63 KLOT 071729
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1129 AM CST Sat Mar 7 2026

.KEY MESSAGES...

- Scattered thunderstorms will move through the area overnight
  and may produce strong to locally damaging winds and a few
  instances of hail.

- Rain is likely late Tuesday into Wednesday, and there is also
  a chance for thunderstorms during this time period.

&&

.DISCUSSION...
Issued at 136 AM CST Sat Mar 7 2026

Through Today:

Warm air advection and broad upper-level diffluence beneath the
right entrance region of an anticyclonically-arcing jet over
the Upper Midwest has fostered the development of a broad swath
of convection that is beginning to enter our western counties at
press time. The overall intensity of this convection has been
held in check thus far by a stabilized planetary boundary layer
and fairly muted instability, with a special 04Z RAOB from DVN
depicting a thermodynamic profile that isn`t particularly
favorable for widespread severe thunderstorms.

However, both this RAOB and regional VWPs have sampled some
fairly strong flow above the somewhat shallow near-surface
stable layer, and evidently, some of this flow that is coincident
with the ongoing convection has been able to penetrate its way
to ground level -- presumably with the assistance of
evaporational processes induced by a fair amount of dry air in
the low- and mid-levels. Recently, several 50+ mph peak wind
gusts were observed in the Quad Cities metro beneath an area of
fairly innocuous radar reflectivity, and would suspect that
similar gusts may be observed over the next few hours as this
area of steady rainfall with embedded lightning continues to
progress northeastward. Have issued a Special Weather Statement
for our western counties to highlight this possibility, and it`s
possible that additional products may need to be issued farther
to the east if this stronger flow aloft continues to find a way
to get transported to ground level.

Otherwise, the more robust-looking (though still somewhat
disorganized) multicell thunderstorms farther to the south don`t
appear to have much of a clear pathway to organize and intensify
appreciably given the less-than-favorable thermodynamic
environment. That said, there are some hints of a potential MCV
developing, and these storms may still nevertheless have the
capability to produce strong to locally damaging winds given the
strong ambient flow aloft, so we`ll continue to monitor radar
trends and surface observations closely. A few instances of
small hail may also occur with these cells as they pulse up
periodically.

It appears that most of the thunderstorm activity should clear
our CWA (save for maybe our far eastern counties) by around or
shortly after sunrise. As we dry out behind the back edge of
the associated rain shield, there could be a few hours-long
period later this morning and early afternoon when some stronger
southwesterly gusts -- perhaps approaching 40 mph at times --
are observed before a well-defined cold front sweeps through the
area from west to east. The timing of this cold frontal passage
will result in many locations observing their high temperatures
for today during the morning hours, with temperatures expected
to fall quickly into the 40s behind the front. A thin line of
strongly-forced showers may also accompany the front. Don`t
think that we`ll be able to destabilize enough for this to cause
any sort of funny business amidst the enhanced low- and mid-level
kinematics, but if surface temperatures end up being a few
degrees warmer than currently anticipated, then this might be
something that we`ll need to keep a closer eye on.


Tonight through Friday:

After today`s cold front clears the area, drier conditions are
expected for the remainder of the weekend and into Monday as two
northern stream waves zip eastward to the north of our area.
Breezy southwesterly winds will help yield unseasonably mild
temperatures on Sunday that look to moderate to potentially
near-record levels on Monday. The second of the aforementioned
disturbances will then send a cold front into the area sometime
Monday night into Tuesday which will likely stall out somewhere
in or near our forecast area as it encounters reinvigorated
south-southwesterly breezes during the daytime on Tuesday. Thus,
there is a fair likelihood that there will be a sharp
(potentially 15-20+ degree) temperature gradient laid out across
our CWA on Tuesday, with unseasonably warm/near-record
temperatures persisting south of the front and more seasonable
temperatures being observed north of the front.

Tuesday into Wednesday, an initially cut-off upper-level low
meandering over the southwestern CONUS and northwestern Mexico
will begin to make more meaningful eastward/northeastward
progress and attempt to phase with an amplifying northern stream
wave somewhere over the central CONUS. As these two disturbances
arrive, anomalously high Gulf moisture (characterized by
potentially record high precipitable water values, per SPC
sounding climatology for ILX) is expected to surge northward
into the Lower Midwest and southern Great Lakes. Widespread
precipitation is thus likely to be observed in the region
Tuesday into Wednesday. Rain should be the predominant
precipitation type observed in our area, but ensemble guidance
depicts several potential scenarios where thermal profiles in at
least our northern counties end up becoming cold enough to
support the occurrence of some type(s) of wintry precipitation
before the precipitation comes to an end on Wednesday.

Existing ensemble spread in the timing and degree of any
potential phasing between the two incoming disturbances, in
addition to persisting uncertainties regarding the placement of
the aforementioned low-level frontal zone, preclude having much
confidence in more specific forecast details for Tuesday into
Wednesday at this time. However, the modeled influx of
unseasonably high moisture content, the ensemble signal
(particularly from the EPS and CMCE) for instability to build
into our area, the presence of a sharp baroclinic zone in the
region, and probabilistic output from multiple machine
learning/AI models all suggest that the late Tuesday into early
Wednesday time frame will be one that will need to be monitored
for potential severe thunderstorms and flash flooding in the
region.

Ogorek

&&

.AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 1129 AM CST Sat Mar 7 2026

Forecast concerns for the terminals...

- Gusty westerly winds around 25-30 kts this afternoon.

- Period of IFR conditions and drizzle early this afternoon
  giving way to MVFR ceilings through this evening.

- Breezy southwest winds Sunday with gusts around 20-25 kts.


A cold front continues to advance across northern IL this
morning and will push through northwest IN by 19z this
afternoon. Along and just behind the front is a some drizzle
which is resulting in a 2-3 hour period of IFR visibilities and
ceilings at the terminals. Outside of the drizzle, the main
concern for this afternoon will be the gusty westerly winds
around 25-30 kts. While gusts will slowly subside this evening,
MVFR ceilings are forecast to persist through at least 03-05z
before scattering out. However, the exact time the ceilings
scatter is somewhat lower confidence so would not be surprised
if ceilings hang on into at least part of the night.

By daybreak Sunday any MVFR ceilings should scatter out
resulting in VFR conditions for the rest of the period. Though,
winds will once again become breezy out of the southwest with
gusts generally around 20-25 kts. That said, a 1-2 hour period
of 28-30 kt winds cannot be completely ruled out Sunday morning
as mixing begins and potentially tags the low-level jet
overhead.

Yack

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 3 PM CST this afternoon for the IL
     and IN nearshore waters.

&&

$$

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